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Isolation of early stages of germ cells in pikeperch (\kur{Sander lucioperca})
GÜNGÖR, Ege
A practical technique for enzymatic dissociation and isolation of pikeperch (Sander lucioperca) (Percidae, Teleostei) early stage germ cells (eGC), including spermatogonia and spermatocytes, is reported in this study. Their potential to differentiate into functional gametes, and transmit genetic information to the next generations makes them suitable for cryopreservation and surrogate reproduction studies by germline chimera. Two different age groups (14 month old and 18 month old) of pikeperch were used to adjust the correct stage of eGC isolation. Finally the 18 month old samples were selected due to their high average gonadal volume (0.513 g). 10 ml PBS + 0.3% trypsin (304 mOsm/kg, pH 8) were used for enzymatic dissociation of testicular cells and they were sorted by centrifugation in Percoll density gradient. eGCs were identified on the basis of their ploidy level by CYSTAIN DNA 1 steps kit (PARTEC) and morphological characteristics trough by light microscopy. Cell counting was performed on histological sections and Percoll gradient layers whit the method of random square counting. The method of isolation enriched the number of eGC from 41.3% to 84.7%, obtained from the 33% of Percoll concentration.
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Physical properties of ultrafine-grained polycrystals of magnesium based alloys
Vrátná, Jitka
The objective of the thesis is the study of microstructure evolution, mechanical properties, defect structure and corrosion resistance of ultra-fine grained magnesium alloy AZ31 prepared by a combined two-step process: the extrusion and the equal-channel angular pressing (ECAP). The microstructure development was studied using light and transmission electron microscopy and electron backscatter diffraction (EBSD). Mechanical properties were studied by microhardness measurement and tensile tests and the defect structure by positron annihilation spectroscopy (PAS). The results of tensile tests indicates that the characteristic stress σ0.2 increases slightly with increasing number of ECAP passes only to the second pass and then decreases significantly with additional ECAP straining. This behaviour is in accordance with the results of PAS. EBSD measurements show that the microstructure of extruded and ECAPed material has a bimodal distribution of grain sizes. The bimodal distribution becomes homogeneous with increasing number of ECAP passes and no remaining large grains are observed after 8 passes. The average grain size in the specimen after 8 passes is in the submicrometer range and the fraction of high-angle grain boundary (HAGB) is approximately 80%. The extruded specimens after 8 ECAP passes show...
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Effect of microstructure on mechanisms of plastic deformation in fine-grained magnesium alloys
Minárik, Peter
In this work were studied effects of the grain refinement on the mechanical properties and the corrosion resistance of magnesium alloys potential for medical applications - AE21 and AE42. Mechanical properties changed after ECAP pressing in consistency with literature data. Enhanced corrosion resistance in AE42 alloy was achieved by the grain refinement. Corrosion layer created on the surface was observed by light and electron microscopy. Effect of the grain size on the character of the corrosion layer was investigated. AE42 alloy is suitable for further investigation as potential biodegradable material. AE21 alloy was excluded from further investigation due to low corrosion resistance even after ECAP treatment.
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Inter-caste differences in the anatomy of termite Embiratermes neotenicus (Termitidae: Syntermitinae)
Vacek, Kryštof ; Šobotník, Jan (advisor) ; Nakládal, Oto (referee)
I devote my thesis to the inner anatomy of termites, as exemplified by Embiratermes neotenicus (Blattodea: Termitoidea: Termitidae: Syntermitinae), in which I studied differences in particular inner organs between worker and soldier. In the first part I described the general body structure typical for sterile castes in termites. I deal with the development, structure, size and also with the purpose of individual organs. These are namely exocrine and endocrine glands, central nervous system, digestive system, fat body, respiratory and circulatory systems, gonads, and muscles. In practical part, I examined worker and soldier of Embiratermes neotenicus by means of optical microscopy. I successfully analysed the development of particular organs and the overall structure of the body. In the discussion section, I compare both castes and put my observations into a broader context.
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Synthesis, properties and product of hydration of strontium aluminate cement
Kocián, Karel ; Bartoníčková, Eva (referee) ; Ptáček, Petr (advisor)
This diploma thesis deals with non-traditional binder, which is strontium aluminate, with his preparation and hydration. The behaviour of binary and ternary mixtures of strontium-calcium-barium aluminates was also studied. These aluminates were prepared by firing an equimolar mixture of aluminum oxide and the appropriate carbonate. Samples prepared this way, including their mixtures, were characterized by analytical methods such as X-ray diffraction analysis (XRD), thermal analysis with evolved gas analysis (TG-DTA and EGA), scanning electron microscopy (SEM), infrared spectroscopy (IR) and calorimetry, with the greatest importance for the study of the hydration process.
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Magnetic ptoperties of the nanocomposite materials
Hendrych, Aleš
Ing. Mgr. Aleš Hendrych Palacky University, Olomouc, December 2009 Supervisor: Doc. RNDr. Roman Kubínek, CSc. Magnetic properties of the nanocomposite materials An enormous advancement in magnetic nanomaterial research during last two decades has been achieved. Much of the effort has been paid to the fundamental physical aspects arising from the preparation process. New trends mainly in the area of information, data storage and sensor technologies are pushing up the development of new magnetic materials to nanometer dimensions. There is still a challenge to meet on the field of the nanomaterials because only in user-specific control limited success was reached so far. Many parameters that affect the final material composition including heat treatment and straining effects should be taken into account due to feasibility of tuning or perking up magnetic nanostructured materials. Thoroughly performed scientific investigations are needed in order to successfully describe and clarify newly developed systems. Naturally, such investigations have to be realized by delicate measuring methods. Therefore, this thesis is dedicated to the development of the particular techniques, namely magneto-optical methods, magneto-optical vector magnetometry, Kerr microscopy and magnetic force microscopy, which are...
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High-temperature embrittlement of 14%Cr ODS ferritic steel in liquid lead environment
Dohnalová, Eva ; Čelko, Ladislav (referee) ; Hadraba, Hynek (advisor)
The thesis deals with the high-temperature embrittlement of 14%Cr ODS ferritic steel in liquid lead environment. The 14%Cr ferritic ODS steel ODM401 manufactured by powder metallurgy technology was used as an experimental material. The effect of the long-term annealing, surface corrosion attack in the melt Pb and Pb-Bi on the microstructure and mechanical properties was described. The subsequent microstructural changes were evaluated by means of scanning electron microscopy and transmission electron microscopy The mechanical behaviour of the experimental material was proven by means of microhardness test, impact test and static tensile test. The fractographical evaluation of fracture surfaces were performed on all samples. The surface attack and outstanding microstructural ganges were found after the long-time exposition of the steel in Pb/Pb-Bi melts at temperature 550°C/1000h and 500°C/1000h respectively. The embrittlement of the steel after exposition in Pb/Pb-Bi melts was comparable to the embrittlement after high-temperature annealing of the steel at temperature 650°C/1000h.
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Low temperature CO oxidation on bimetallic structures
Hanyš, Petr ; Nehasil, Václav (advisor) ; Janovská, Michaela (referee) ; Plšek, Jan (referee)
Title: Low temperature CO oxidation on bimetallic structures Author: Petr Hanyš Department: Department of Surface and Plasma Science Supervisor: Doc. RNDr. Václav Nehasil, Dr., Department of Surface and Plasma Science Abstract: Bimetallic system Sn-Rh in the form of the model Sn/Rh(111) system, supported Rh+Sn/Al2O3 and Rh/SnO2 clusters and Rh/SnO2 and Rh+Sn/Al2O3 powder samples was studied using synchrotron radiation photoelectron spectroscopy (SRPES), X-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy (TDS), molecular beams (MB), transmission and scanning electron microscopy (TEM, SEM), powder X-ray diffraction (XRD) and high pressure reactor within the framework of the study. It was found that formation of Sn-Rh alloy influences catalytic properties of Rh by lowering CO adsorption energy and capacity. It was also found that presence of Rh in this bimetallic system mediates reversible oxidation/reduction of Sn/SnO2, whereas Sn oxide acts as an oxygen reservoir for low temperature CO oxidation. Keywords: bimetallic systems, rhodium, tin, low temperature CO oxidation
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Semiquantitative bacteriological examination of urine
VITANOVSKÁ, Alena
Urine is a liquid product of metabolism excreted through the kidneys. It refers to the overall health of the body. Urinary tract infections are the second most common disease in the population caused by various pathogens. E. coli is the most frequent pathogen. The increase in resistance of bacterial pathogens to antibiotics is related to the high incidence of persistent infections and their treatment. The main objectives of this thesis are to introduce the bacteriological examination of urinary tract infections and mastering the art semiquantitative bacteriological examination of urine and other processes leading to the diagnosis of urinary pathogens using in the Medical Microbiology Department of Klatovská nemocnice, a.s.. Then, based on the results taken from LIS OLM to evaluate the obtained results and to compare them with the literature. The first part deals with the definition of basic concepts that are associated with urinary tract infections, and its infections and occurring pathogens. The various phases of laboratory procedure are described. In particular, analytical part of laboratory procedure which deals with theoretical description of methods of laboratory diagnostics. The procedures of identification methods, which are used in the Medical Microbiology Department of Klatovská nemocnice, a.s. are described in the methodology. That means semiquantitative examination, microscopy, various biochemical tests for pathogens identification and process for the determination of sensitivity. The research results are evaluated using simple statistics in tables and graphs. In the year 2014 8623 urine samples were examined. 6267 samples came from hospital patients. The samples from hospital patients were for the statistical evaluation. From these samples 1260 were cases of E. coli, Enterococcus 829 cases and 297 cases of Proteus. For further statistical evaluation is carried out with E. coli which determine sensitivity to nitrofurantoin such were 1030. From that 819 women and 211 men. The highest incidence of this pathogen was among women in the age group over 61 years, it were the 542 patients. For men the capture also the highest over the age of 61 years, with 166 patients. The lowest detection of E. coli in both men and women was the lowest compared to other categories of age 7-17.
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